Sporadic outbreaks of aflatoxicosis occur in dogs when they consume contaminated dog food. During 2011, low-cost brands of pelleted dog food were contaminated with very high concentrations of aflatoxins. Approximately 100 dogs were presented to the Onderstepoort Veterinary Academic Hospital. Clinically, the dogs were depressed to collapsed and icteric, with haematemesis, melaena and haematochezia. The most common pathological findings were icterus, gastro-enterorrhagia and hepatosis. On histopathological examination, fatty hepatosis and bile duct proliferation were observed. A consistent, very characteristic finding was the presence of a blue-grey granular material within the bile ducts. A total of 124 samples of the dog food fed to the affected dogs was analysed to determine aflatoxin concentrations. Concentrations ranged from below the limit of quantification (< 5 mg/kg) to 4946 mg/kg and six samples were submitted to determine the ratio of aflatoxins in the feed. It is estimated that well over 220 dogs died in the Gauteng Province of South Africa as a result of this aflatoxin outbreak.